Metal coating apparatus



VPatented Oct. 17, 1933 UNITED STATES PATENT OFFICE METAL COATING APPARATUS Frank P. Townsend, East Orange, N. J.

Application February 12, 1931. Serial No. 515,148

6 Claims.

This invention relates to metal coating apparatus and, while not limited thereto, relates t0 apparatus for coating metal sheets and strips with tin, zinc or other metals and has for one of its objects the provision of an apparatus of this class especially adapted for coating strip material or sheet material carried by a suitable conveyer.

Another object is to provide an apparatus of this class so constructed, designed and operated as to prevent oxidation of the molten coating metal in the pot and on the articles being coated.

A further object is to provide an apparatus of this class especially adapted for providing a uniform coating without regard to any unevenness in the thickness of the metal being coated.

A still further object is to provide an apparatus in which the temperature of the coated material may be controlled after passing from the coating metal so as to control the thickness of the coating.

Other objects and advantages will become readily apparent to those skilled in the art from the following specification taken with the accompanying drawing.

The drawing is a sectional elevation showing one arrangement of apparatus embodying my invention.

Referring more particularly to the drawing, the numeral 2 designates the base of the furnace wall of the apparatus which encloses a furnace or heating chamber 3 in which a gaseous or other fuel burner 4 is mounted. Y

It will be understood that I do not wish to be limited to the use of the particular burner 4 shown in the drawing, since other burners may be substituted therefor or other means of heating the bath may be used such as standard electrically heated or gas-fired muiiles which may be inserted in the bath.

A pot 5 is mounted on the Wall 2 and extends down into the furnace chamber 3. The pot 5 has a curved bottom 6 and a transverse dividing Wall 7 which extends downwardly from the upper end of the pot to a point materially below the level of the molten metal 8 so as to divide the pot into inlet and exit sides.

The inlet side of the pot extends upwardly a material distance above the level of the molten metal 8 to form an inlet chamber 9 which is normally closed at its upper end by a closure 10 hav-1 ing a narrow inlet slot or restricted opening 12 therein through which the material to be coated enters.

(Cl. ill-12.5)A

A heating element 13 is preferably provided in the inlet chamber 9 and serves to preheat the material to be passed through the coating metal at a greater speed than possible when said material enters the coating metal cold.

A pipe 14 enters the chamber 9 through which a supply of non-oxidizing huid, such as gas or steam, is permitted to enter the chamber to prevent oxidation of the coating metal and the material to be coated.

If desired, a layer of flux 15 may be maintained on the top of the molten metal in the chamber 9. However, this is not necessary since the flux may be applied to the metal prior to passing it into the chamber.

A finishing stack 16 is mounted on and communicates with the exit side of the pot 5 and extends upwardly a material distance above the inlet chamber 9. The stack 16 is divided intermediate its ends by a diaphragm 17 into a finishing chamber 18 and a cooling chamber 19. The diaphragm 17 is provided with a narrow slot 20 through which the coated material passes and the upper end of the stack is closed, as at 21, except for a narrow slot 22 through which the finished material passes to the atmosphere.

A heater coil 23 or other source of heat is mounted in the nishing chamber 18 to maintain the temperature in the chamber at approximately the melting temperature or slightly above the melting temperature of the coating so that as the coated material moves upwardly through the chamber the excess coating will drain back into the bath of molten coating in the pot. This draining olf of the excess coating material will give a uniformity of coating without regard to any unevenness in the thickness of the material being coated and by regulating the temperature of the bath of coating material and the temperature of the chamber 18, the thickness of the coating may be readily controlled.

A cooling coil 24 is mounted in the cooling chamber 19 so as to surround the coated material passing through said chamber and is adapted to reduce the temperature of the chamber 19 and thereby the temperature of the coated material so as to solidify or set the coating before it leaves said chamber and before it contacts with any solid material.

While not shown, it will be understood that suitable standard and well known regulating means may be employed, if desired, to regulate the heat generated by the elements 13 and 23 and to regulate the amount of cooling :duid passing through the coil 2e.

The chambers 18 and 19 are adapted to be filled with a non-oxidizing fluid, such as gas or steam, and therefore a iiuid supply pipe 25 enters the lower end of the stack and the uid supplied at this point lls the chambers and escapes through the exit slot 22.

The non-oxidizing fluid in` the chambers 18 and 19 serves a twofold purpose of avoiding oxidation of the molten coating on the coated material and in the bath.

For the sake of simplicity in illustrating the apparatus, it is shown as adapted for coating continuous strip metal, and a roller 26 is shown for supporting the material above the entering chamber 9. The strip material is adapted to be passed over the roller 26 then through the slot 12 and down through the chamber 9 into the pot 5 and under a roller 27 in the molten coating material, then upwardly through the pot 5 and stack 16 through the exit slot 22 and between pinch-rollers 28. The material is preferably passed from the rollers 28 to a take-up block 29 or other suitable point of storage.

The pinch-rollers 28 may be power-operated, if desired, or the material may be pulled through the apparatus by the take-up block.

If sheet material is being coated it may be carried through the coating apparatus by any suitable conveying means or such sheets may be attached together by welding or other mechanical means to form in effect a continuous strip.

While I have shown and described a certain specic construction of' apparatus, it will be understood that I do not wish to be limited thereto, since various modications may be made without departing from the scope of my invention, as dened in the appended claims.

I claim:

1. Apparatus for coating metal strips, sheets and the like with molten coating material comprising a pot for containing the molten coating material, means for applying heat to melt and maintain said coating material molten, said pot having its inlet side elevated materially above the level of the coating material to form an inlet chamber, said chamber having its upper end closed except for a narrow slot through which the material to be coated passes, a finishing stack communicating with the exit side of said pot and extending upwardly a material distance above said pot, said stack being divided intermediate its ends by a diaphragm, the portion of the stack below said diaphragm forming a nishing chamber in which the excess coating drains from the material and the portion of said stack above said diaphragm forming a cooling chamber in which the coating cools and sets, means for supplying heat to said iinishing chamber to maintain said coating material molten while the coated material is passing through said chamber, and means in said cooling chamber for artificially cooling the coated material to set the coating.

` 2. Apparatus for coating metal strips, sheets and the like with molten coating material comprising a pot for containing the molten coating material, means for applying heat to melt and maintain said coating material molten, said pot having is inlet side elevated materially above the level of the coating material to form an inlet chamber, said chamber having its upper end closed except for a narrow slot through which the material to be coated passes, a finishing stack communicating with the exit side of said pot and extending upwardly a material distane above said pot, said stack being divided intermediate its ends by a diaphragm, the portion of the stack below said diaphragm forming a nishing chamber in which the excess coating drains from the material and the portion of said stack above said diaphragm forming a cooling chamber in which the coating cools and sets, means for supplying non-oxidizing fluid to said inlet chamber and said stack, means for supplying heat to said finishing chamber to maintain said coating material molten while the coated material is passing through said chamber, and means in said cooling chamber for articially cooling the coated material to set the coating.

3. Apparatus for coating metal strips, sheets and the like with molten coating material comprising a pot for containing the molten coating material, means for applying heat to melt and maintain said coating material molten, said pot having, its inlet side elevated materially above the level of the coating material to form an inlet chamber, said chamber having its upper end closed except for a narrow slot through which the material to be coated passes, a iinishing stack communicating with the exit side of said pot and extending upwardly a material distance above said pot, said stack being divided intermedate its ends by a diaphragm, the portion of the stack below said diaphragm forming a. iinish- :ng chamber in which the excess coating drains from the material and the portion of said stack above said diaphragm forming a cooling chamber in which the coating cools and sets, means for supplying non-oxidizing fluid to said inlet chamber and said stack, means for supplying heat to said inlet chamber and said nishing chamber, and means in said cooling chamber for articially cooling the coated material to set the coating.

4. Apparatus for coating metal work such as strips, sheets and the like with molten coating material comprising a pot for containing the molten coating material, means for applying heat to melt and maintain said coating material in said pot molten, said pot being provided with an inlet chamber at its inlet end, said chamber having its inlet end closed except for a narrow opening through which the work to be coated passes into the coating material in said pot, the work being coated with molten coating material as it passes through the body of molten material in said pot, a finishing chamber communicating with the exit side of said pot and extending materially beyond said pot and through which the coated work passes from said pot, and means in said chamber adjacent said pot for supplying heat to said chamber to maintain the coating material on said Work molten to permit the removal of excess coating material from said Work.

5.' Apparatus for coating metal Work such as strips, sheets and the like with molten coating material comprising a pot for containing the molten coating material, means for applying heat to melt and maintain said coating material in said pot molten, said pot being provided with an inlet chamber at its inlet end, said chamber having its inlet end closed except for a narrow opening through which the work to be coated passes into the coating material in said pot, the work being coated with molten coating material as it passes through the body of molten material in said pot, a stack communicating with the exit side of said pot and extending materially beyond said pot and through which the coated Work passes from said pot, said stack being divided intermediate its ends by a diaphragm, the portion of said stack between said diaphragm and said pot forming a nishing chamber in which excess coating is removed from the Work and the portion of said stack beyond said diaphragm forming a cooling chamber in which the coating cools and sets on the work, means for supplying heat to said finishing chamber to maintain the coating material on said work molten while the material is passing through said chamber, and means in said cooling chamber for artificially cooling the coated work to set the coating.

6. Apparatus for coating metal work such as strips, sheets and the like with molten coating material comprising a pot for containing the molten coating material, means for applying heat to melt and maintain said coating material molten, the work being adapted to pass through the molten coating material in said pot from one side of the pot to the other and to be coated with molten coating material as it exits from said pot, said pot being provided with a stack communicating with the exit side of said pot and extending materially beyond said pot and through which the, coated work passes from said pot, and means in said stack adjacent said pot for supplying heat to said stack suilicient to maintain the coating material on said work molten to permit the removal of excess coating material from th work.

FRANK P. TOWNSEND. 

